Are you saying that you cannot get Fox Sports South when using the Spectrum TV app on a mobile device?
Is Fox Sports South in the package to which you subscribe?
Is your device connected to the home network that is powered by Spectrum internet where you have the tv subscription?
Are you able to sign into the Fox Sports Go app?
As is so often the case with professional sports leagues, if this complaint is about a single event or on a single day, there is probably a contractual blackout covering the subscriber's area.
If the problem continues, this is not the first time users have reported that Fox Sports South is missing on the Spectrum app. Since I don't remember an obvious resolution, I'll try to search back in the forum postings from the last few months.